U.S. patent number 9,074,043 [Application Number 13/588,981] was granted by the patent office on 2015-07-07 for compound for carrier transport, element and electronic device using the same.
This patent grant is currently assigned to HARVATEK CORPORATION, Tzeng-Feng Liu. The grantee listed for this patent is Feng-Chih Chang, Chih-Chia Cheng, Yu-Lin Chu. Invention is credited to Feng-Chih Chang, Chih-Chia Cheng, Yu-Lin Chu.
United States Patent |
9,074,043 |
Chang , et al. |
July 7, 2015 |
Compound for carrier transport, element and electronic device using
the same
Abstract
The present invention provides a compound of formula I
##STR00001## wherein A, B and C are a repeating unit; each of A and
B is an optionally substituted group for forming a conjugated
polymer; C is a crosslinkable group; and n is an integer equal to
or greater than 1. The present invention further provides an
element and an electronic device using the compound of formula I,
and more particularly, provides a light emitting diode (LED) device
using the compound of formula I.
Inventors: |
Chang; Feng-Chih (Hsinchu,
TW), Chu; Yu-Lin (Hsinchu, TW), Cheng;
Chih-Chia (Yunlin County, TW) |
Applicant: |
Name |
City |
State |
Country |
Type |
Chang; Feng-Chih
Chu; Yu-Lin
Cheng; Chih-Chia |
Hsinchu
Hsinchu
Yunlin County |
N/A
N/A
N/A |
TW
TW
TW |
|
|
Assignee: |
HARVATEK CORPORATION (Hsinchu,
TW)
Liu; Tzeng-Feng (Hsinchu, TW)
|
Family
ID: |
50100494 |
Appl.
No.: |
13/588,981 |
Filed: |
August 17, 2012 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20140051826 A1 |
Feb 20, 2014 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08G
61/124 (20130101); C08G 61/12 (20130101); H01L
51/0035 (20130101); H01L 51/0072 (20130101); C08G
2261/512 (20130101); C08G 2261/91 (20130101); H01L
51/5088 (20130101); C08G 2261/92 (20130101); Y02E
10/549 (20130101); C08G 2261/3241 (20130101); C08G
2261/95 (20130101); C08G 2261/135 (20130101); C08G
2261/1432 (20130101); C08G 2261/411 (20130101); H01L
51/006 (20130101); C08G 2261/149 (20130101); C08G
2261/3162 (20130101); C08G 2261/94 (20130101); C08G
2261/143 (20130101) |
Current International
Class: |
H01L
51/50 (20060101); C08G 61/12 (20060101); H01L
51/00 (20060101) |
Field of
Search: |
;257/40
;528/367,423 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2002536492 |
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2003301033 |
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Oct 2003 |
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JP |
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2003221447 |
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Aug 2004 |
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JP |
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2006257196 |
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JP |
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JP |
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2012102286 |
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2011526420 |
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Aug 2012 |
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JP |
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Other References
USPTO structure search, Mar. 2015. cited by examiner .
Jiang et al., Perfluorocyclobutane-Based Arylamine
Hole-Transporting Materials for Organic and Polymer Light-Emitting
Diodes, Advanced Functional Material, 2002, vol. 12, No. 11-12, pp.
745-751. cited by applicant .
Niu et al., Crosslinkable Hole-Transport Layer on Conducting
Polymer for High-Efficiency White Polymer Light-Emitting Diodes,
Advanced Material, 2007, vol. 19, pp. 300-304. cited by applicant
.
Shao et al., Long-Lifetime Polymer Light-Emitting Electrochemical
Cells Fabricated with Crosslinked Hole-Transport Layers, Advanced
Materials, 2009, vol. 21, pp. 1972-1975. cited by applicant .
Koh et al., Optical Outcoupling Enhancement in Organic
Light-Emitting Diodes: Highly Conductive Polymer as a Low-Index
Layer on Microstructured ITO Electrodes, Advanced Materials, 2010,
vol. 22, pp. 1849-1853. cited by applicant .
Chu et al., A New Supramolecular Hole Injection/Transport Material
on Conducting Polymer for Application in Light-Emitting Diodes,
Advanced Materials, 2012, pp. 1-5. cited by applicant .
Cheng et al., Biocomplementary Interaction Behavior in DNA-Like and
RNA-Like Polymers, Journal of Polymer Science: Part A: Polymer
Chemistry, 2009, vol. 47, pp. 6388-6395. cited by applicant .
Kim et al., Poly(3,4-ethylenedioxythiophene) Derived from
Poly(ionic liquid) for Use as Hole-Injecting Material in Organic
Light-Emitting Diodes, Macromolecular Rapid Communications, 2009,
vol. 30, pp. 1477-1482. cited by applicant .
Cheng et al., Hierarchical Structure Formed from Self-complementary
Sexuple Hydrogen-bonding Arrays, RSC Advances, 2011, vol. 1, pp.
1190-1194. cited by applicant.
|
Primary Examiner: Listvoyb; Gregory
Attorney, Agent or Firm: Li & Cai Intellectual Property
(USA) Office
Claims
What is claimed is:
1. A compound of formula I ##STR00006## wherein A, B and C are a
repeating unit, wherein the repeating unit is:
1-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl)butyl]--
1,2,3,4-tetrahydropyrimidine-2,4-dione;
9-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl)butyl]--
9H-purin-6-amine;
1-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl)butyl]--
5-methyl-1,2,3,4-tetrahydropyrimidine-2,4-dione;
4-amino-1-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl-
)butyl]-1,2-dihydropyrimidin-2-one; or
2-amino-9-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl-
)butyl]-6,9-dihydro-1H-purin-6-one; n is an integer equal to or
greater than 1.
2. A conductive film, comprising the compound of formula I
according to claim 1.
3. A carrier transport layer, comprising the compound of formula I
according to claim 1.
4. The carrier transport layer according to claim 3, wherein the
carrier transport layer is a hole transport layer.
5. An electronic device, comprising the conductive film according
to claim 2.
6. An electronic device, comprising the carrier transport layer
according to claim 3.
7. The electronic device according to claim 6, wherein the
electronic device is an electroluminescent device or a
transistor.
8. The electronic device according to claim 7, wherein the
electroluminescent device is a light-emitting diode.
9. A solar cell, comprising the carrier transport layer according
to claim 3.
10. A light detector, comprising the carrier transport layer
according to claim 3.
Description
FIELD OF THE INVENTION
The present invention relates to a novel compound for carrier
transport, particularly, to an element and electronic device using
the novel compound, and more particularly, to a LED device using
the novel compound.
BACKGROUND OF THE INVENTION
Organic and polymer light-emitting diodes (OLED and PLED) have
drawn considerable attention because of their low power
consumption, light weight, fast response and wide viewing angle.
Charge transport is an important factor with regard to the
performance of these devices. For high-performance LED devices,
charge injection and transport from both anode and cathode must be
balanced off by excitons formed in a light emission layer.
Generally, LED devices include three layers sealed between two
electrodes, including a hole injection/transport layer (HITL), an
electron-emitting layer (EML) and an electron-transporting layer
(ETL). Package configurations allow each layer to be optimized
individually for charge injection, transport and emission.
Currently developed polymer materials for the hole
injection/transport layer (HITL) can mainly be divided into two
types based on chemical bonds formed therein, i.e. ionic bond and
covalent bond.
Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)
(abbreviated as PEDOT-PSS hereinafter) as shown in FIG. 1 is one
material formed by ionic bonding. Studies on organic materials
possessing high hole-injection have been focused on PEDOT-PSS due
to its reasonable ionization potential (I.sub.p=-5.2 to -5.3 eV),
high conductivity (.about.1-10 S/cm) and good hole-injection
ability. However, PEDOT-PSS is ionic, acidic and fabricated from
water dispersion. Water is relatively more destructive than oxygen
for OLEDs and PLEDs. Therefore, PEDOT-PSS is not very stable in the
LED architecture. Due to the drawbacks of its material
characteristics, currently, PEDOT-PSS cannot be effectively used in
the process of large-scale coating.
Further, PEDOT-PSS can be used as a conventional organic transistor
element. However, PEDOT has a poor orientational property in an
electrode and cannot express a sufficient carrier transport
property as an electrode material.
Covalently cross-linked hole injection/transport materials
(abbreviated as HITM) leading to the formation of solvent-resistant
hole-injection layers have also been extensively studied. Varieties
of thermally, photochemically and electrochemically cross-linked
materials can overcome the interfacial mixing caused by solution
processing. For example, thermosetting polymers formed by covalent
bonding as shown in FIG. 2 (Adv. Fun. Mater. 2002. 12 745.; Adv.
Mater. 2007, 19, 300.; Adv. Mater. 2009, 21, 1972.) have proper
molecular energy levels (Highest Occupied Molecular Orbital (HOMO)
I.sub.p=-5.3 eV) and excellent hole injeciotn capacities.
Therefore, electronic elements made from the thermosetting polymers
have good efficiency. Although the thermosetting polymers formed by
covalent bonding do not have the drawbacks of PEDOT-PSS, the
property of the thermosetting polymers makes them lack of
workability. In addition, the processes for manufacturing
electronic elements by the thermosetting polymers are more complex
and harsh (for example, it needs a high temperature of over
200.degree. C. to perform thermal curing). Since the cost for
manufacturing electronic elements by the thermosetting polymers is
high, the polymers currently are suitable for use in small devices
of labs and do not have the potential for highly commercial mass
production.
BRIEF SUMMARY OF THE INVENTION
For overcoming many drawbacks of current materials, a novel and
cost effective material containing neither ion nor hydrophilic
functionality to replace PEDOT-PSS and thermosetting polymers has
been actively pursued. The inventors, therefore, provide a novel
compound that leads to a physically cross-linked structure formed
by highly complementary non-covalent bonding and can act as well as
the covalently cross-linked materials without additional
processes.
In one aspect, the present invention provides a compound of formula
I
##STR00002## wherein A, B and C are a repeating unit; each of A and
B is an optionally substituted group for forming a conjugated
polymer; C is a crosslinkable group; and n is an integer equal to
or greater than 1.
Another aspect of the present invention is a compound of formula I,
wherein A and B are the same or different and each of them is one
independently selected from the group consisting of optionally
substituted triphenylamine, optionally substituted carbazole,
optionally substituted thiophene, optionally substituted fluorene,
optionally substituted p-phenylene vinylene and a combination
thereof; C is one selected from the group consisting of an
amide-containing group, a carboxyl-containing group, a
hydroxyl-containing group, an amino-containing group, a
halogen-containing group, a base-containing group, and a
combination thereof; and a substituent for A or B is one
independently selected from the group consisting of C.sub.1-15
alkyl and C.sub.6-10 aryl.
According to the present invention, the examples of the
base-containing group may include adenine, thymine, cytosine,
guanine, uracil, a combination thereof and the like. Preferably,
the base-containing group is adenine or uracil. In addition, the
examples of C may be
##STR00003## a combination thereof etc. and a substituent for R1
may be C.sub.1-15 alkyl or C.sub.6-10 aryl.
In a further aspect, the present invention provides a compound of
formula I, wherein A is optionally substituted triphenylamine, B is
optionally substituted carbazole and a substituent for A and B is
butyl.
In another aspect, the present invention provides a compound of
formula I, provided that when C is the crosslinkable group, both A
and B are not thiophene, fluorene or p-phenylene vinylene at the
same time; when C is the crosslinkable group, A and B are
different; when both A and B are optionally substituted carbazole
at the same time, C is not guanine; or when A is optionally
substituted fluorene and B is optionally substituted carbazole, C
is not guanine.
In one embodiment of the compound of formula I of the present
invention, the repeating unit is
1-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl)butyl]--
1,2,3,4-tetra hydropyrimidine-2,4-dione;
9-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl)butyl]--
9H-purin-6-amine;
1-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl)butyl]--
5-methyl-1,2,3,4-tetrahydropyrimidine-2,4-dione;
4-amino-1-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl-
)butyl]-1,2-dihydropyrimidin-2-one; or
2-amino-9-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl-
)butyl]-6,9-dihydro-1H-purin-6-one.
In another aspect of the present invention, a conductive film
including any one of the aforementioned compounds is provided.
In still another aspect of the present invention, a carrier
transport layer including any one of the aforementioned compounds
is provided. Preferably, the carrier transport layer may be a hole
transport layer.
In yet another aspect of the present invention, an electronic
device is provided, wherein a conductive film is included and the
conductive film includes any one of the aforementioned
compounds.
One aspect of the present invention is to provide an electronic
device that includes a carrier transport layer and the carrier
transport layer includes any one of the aforementioned compounds.
Preferably, the electronic device may be an electroluminescent
device or a transistor. More preferably, the electroluminescent
device may be a light-emitting diode device. Particularly, the
light-emitting diode device may be an organic light-emitting diode
device.
In another aspect of the present invention, a solar cell is
provided, wherein a carrier transport layer is included and the
carrier transport layer includes any one of the aforementioned
compounds.
In another aspect of the present invention, a light detector is
provided, wherein a carrier transport layer is included and the
carrier transport layer includes any one of the aforementioned
compounds.
In a further aspect, the present invention provides a method for
manufacturing an electronic element that includes a layer formed by
using any one of the aforementioned compounds. Preferably, the
layer may be a film.
In another aspect of the present invention, a method for
manufacturing an electronic device is provided, wherein the method
includes the step of using any one of the aforementioned compounds.
The examples of the electronic device may be an electroluminescent
device or a transistor. Preferably, the electroluminescent device
may be a light-emitting diode device. More preferably, the
light-emitting diode device may be an organic light-emitting diode
device.
Since the compound of the present invention is not a polymer formed
by ionic bonding, it has excellent environment stability. The
present invention not only has the properties of current hole
injection/transport materials, but also can overcome many defects
of current techniques. In addition, the process for manufacturing
the present invention is easy and the solvent-resistant ability of
the element formed by the present invention is enhanced due to the
property of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the chemical structure of PEDOT-PSS;
FIG. 2 shows the chemical structure of a thermosetting polymer;
FIG. 3 shows the FTIR spectrogram of PTC, PTC-A and PTC-U
(2400.about.3700 cm.sup.-1);
FIG. 4 shows the FTIR spectrogram of PTC, PTC-A and PTC-U
(1400.about.2000 cm.sup.-1);
FIG. 5 shows the TGA diagram of PTC, PTC-A and PTC-U;
FIG. 6 shows the DSC diagram of PTC, PTC-A and PTC-U;
FIGS. 7A-7C show the solvent resistant abilities of PTC, PTC-A and
PTC-U, respectively;
FIG. 8 shows the I-V diagram of the structures with the thin films
formed by PTC, PTC-A and PTC-U, respectively;
FIG. 9 shows the energy level diagram for different materials;
FIG. 10 shows the I-V diagram of the elements with the thin films
formed by PTC, PTC-A and PTC-U, respectively;
FIG. 11 shows the L-V diagram of the elements with the thin films
formed by PTC, PTC-A and PTC-U, respectively;
FIG. 12 shows a process for manufacturing a LED device;
FIG. 13 shows the EQE-V diagram of the OLED devices with the thin
films formed by PTC, PTC-A and PTC-U, respectively;
FIG. 14 shows the LE-V diagram of the OLED devices with the thin
films formed by PTC, PTC-A and PTC-U, respectively;
FIG. 15 shows the PE-V diagram of the OLED devices with the thin
films formed by PTC, PTC-A and PTC-U, respectively; and
FIGS. 16A-16D show the light performance diagrams of the elements
and OLED devices with the thin films formed by PTC-U/PTC-A in
ratios of 1:4 and 1:10, respectively.
DETAILED DESCRIPTION OF THE INVENTION
The following illustrative embodiments are provided to illustrate
the disclosure of the present invention. These and other advantages
and effects of the present invention can be apparently understood
by those in the art after reading the disclosure of this
specification.
As used herein, the term "conjugated polymer" refers to an
intrinsic conductive polymer, in which the main chain of the
polymer is formed by means of alternating single and double
bonds.
As used herein, the term "crosslinkable group" refers to a group
that can form crosslinking by a hydrogen bond. Examples of a
crosslinkable group, which can form crosslinking by such a hydrogen
bond, may include an amide group, a carboxyl group, a hydroxyl
group, an amino group, a halogen-containing group, a
base-containing group, etc.
As used herein, the term "halogen" refers to iodine, bromine,
chlorine or fluorine.
As used herein, the term "base-containing group" refers to any
group including a base. The examples of base may include adenine,
cytosine, guanine, uracil, thymine, etc. and the examples of the
base-containing group may also include adenine, cytosine, uracil,
guanine and thymine.
As used herein, "alkyl" refers to a hydrocarbon chain, typically
ranging from about 1 to 15 carbon atoms in length. Such hydrocarbon
chains are preferably but not necessarily saturated and may be
branched or straight chain, although typically straight chain is
preferred. Exemplary alkyl groups may include methyl, ethyl,
propyl, butyl, pentyl, 1-methylbutyl, 1-ethylpropyl,
3-methylpentyl, and the like.
As used herein, "aryl" refers to one or more aromatic rings,
typically ranging from about 6 to 10 carbon atoms. Aryl may include
multiple aryl rings that may be fused, such as naphthyl, or
non-fused, such as biphenyl. Aryl rings may also be fused or
non-fused with one or more cyclic hydrocarbon, heteroaryl, or
heterocyclic rings. Exemplary aryl groups may include phenyl,
naphthyl and the like.
As used herein, "hole transport layer (HTL)" refers to an element
for facilitating holes transport. For example, when inserting a
hole transport layer between indium tin oxide (abbreviated as ITO
hereinafter) and an emissive layer, the hole-transport barrier is
remarkably reduced to facilitate holes transport. Moreover, a gap
state in the band gap of HTL is found to further improve holes
injection at the interface. This phenomenon can explain why an
electroluminescent device (especially OLED devices) having HTL
shows improved performance. Examples of the material used for a
hole transport layer may include triphenyl diamine (TPD),
N,N-bis(naphthalen-1-yl)-N,N-bis(phenyl)benzidine (NPB, Kodak),
polyvinylcarbazole (PVK), Spiro-TPD (Covion), Spiro-NPB (Covion)
and the like.
EXAMPLE 1
Synthesis of 4-butyl-N,N-bis(4-bromophenyl)aniline (compound 1)
##STR00004##
As shown in scheme 1, toluene (50 ml), butyl-aniline (4.23 mL, 26.8
mmol), 1-bromo-4-iodobenzene (16.68 g, 59 mmol),
1,10-phenanthroline (0.18 g, 0.97 mmol), cuprous chloride (CuCl)
(0.1 g, 0.95 mmol) and potassium hydroxide (KOH) (13.67 g, 243
mmol) were added sequentially to a 250 ml three-necked flask
equipped with condenser, magnetic stirrer, nitrogen inlet and
outlet under nitrogen. The reaction mixture was heated to reflux in
30 min and was stirred at reflux for 48 h. Then, the mixture was
cooled to 75.degree. C., and 100 ml of toluene and 100 ml of
distilled water were used in extraction. The toluene phase was
separated, dried with anhydrous magnesium sulfate (MgSO.sub.4),
filtered and vacuum distilled. The crude product was purified by
silica column chromatography using toluene as eluent to give
colorless oil (3.8 g, 31%).
.sup.1H NMR (300 MHz, CDCl.sub.3, .delta.): 7.30 (dd, 4H; Ar H),
7.07 (d, 2H; Ar H), 6.96 (d, 2H; Ar H), 6.90 (dd, 4H; Ar H), 2.56
(t, 2H; CH.sub.2), 1.63-1.52 (m, 2H; CH.sub.2), 1.41-1.29 (m, 2H;
CH.sub.2), 0.93 (t, 3H; CH.sub.3).
.sup.13C NMR (300 MHz, CDCl.sub.3, .delta.): 146.7, 144.4, 138.8,
132.2, 129.4, 125.0, 114.9, 35.0, 33.6, 22.4, 14.0.
HRMS (ESI, m/z): [M+H].sup.+ calcd for C.sub.22H.sub.21NBr.sub.2,
457.0041. found, 457.0039.
EXAMPLE 2
Synthesis of
4-butyl-N,N-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-4-phenyl)-aniline
(compound 2)
As shown in scheme 1, to a solution of
4-butyl-N,N-bis(4-bromophenyl)-aniline (2.02 g, 4.4 mmol) in
anhydrous tetrahydrofuran (THF, 44 mL) at -78.degree. C. was added
n-butyl lithium (n-BuLi, 4.4 mL, 11.1 mmol, 2.5 M in hexane). The
mixture was stirred at -78.degree. C. for 45 min.
2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.7 mL, 13.2
mmol) was added rapidly to the solution. The mixture was stirred
for 2 h at -78.degree. C. The mixture was poured into water and
extracted with diethyl ether. The organic extracts were combined
and washed with brine. The solvent was removed under reduced
pressure, and the crude product was purified by recrystallization
from methanol to get colorless crystals (1.36 g, 56%, mp:
204-206.degree. C.).
.sup.1H NMR (300 MHz, CDCl.sub.3, .delta.): 7.64 (d, 4H; Ar H),
7.03 (m, 8H; Ar H), 2.56 (t, 2H; CH.sub.2), 1.63-1.53 (m, 2H;
CH.sub.2), 1.38-1.31 (m, 26H; CH.sub.2 and C.sub.8H.sub.24), 0.92
(t, 3H; CH.sub.3).
.sup.13C NMR (300 MHz, CDCl.sub.3, .delta.): 150.5, 144.7, 139.0,
135.9, 129.4, 126.2, 122.7, 83.8, 35.3, 33.9, 24.9, 22.5, 14.3.
HRMS (ESI, m/z): [M+H].sup.+ calcd for
C.sub.34H.sub.45B.sub.2NO.sub.4, 553.3534. found, 553.3539.
EXAMPLE 3
Synthesis of 4-bromobutyl-9(3,6-dibromocarbazole) (compound 3)
As shown in scheme 1, the following reagents were placed in a
reaction flask fitted with a condenser: product
3,6-dibromo-9H-carbazole (6.5 g, 0.02 mol), powdered anhydrous
potassium carbonate (5.53 g, 0.04 mol), anhydrous acetonitrile (80
mL) and 1,4-diromobutane (25 mL, 0.2 mol). The reaction vessel was
purged with argon and this atmosphere was maintained throughout the
reaction. The reaction mixture was stirred and heated at reflux in
an oil bath at 95.degree. C. for 36 h. Finally, the reaction
mixture was filtered, the solvent was evaporated, and the residue
was recrystallized from petroleum ether to give crystals (6.9 g,
75%).
.sup.1H NMR (300 MHz, CDCl.sub.3, .delta.): 8.10 (d, 2H; Ar H),
7.54 (dd, 2H; Ar H), 7.25 (d, 2H; Ar H), 4.25 (t, 2H; CH.sub.2),
3.36 (t, 2H; CH.sub.2), 2.04-1.95 (m, 2H; CH.sub.2), 1.89-1.80 (m,
2H; CH.sub.2).
.sup.13C NMR (300 MHz, CDCl.sub.3, .delta.): 134.4, 124.4, 118.9,
107.6, 105.8, 37.8, 28.4, 25.5, 22.9.
EXAMPLE 4
Synthesis of 4-uracilbutyl-9 (3,6-dibromocarbazole) (compound 4,
R=uracil)
As shown in scheme 1, the following reagents were placed in a
reaction flask fitted with a condenser:
4-bromobutyl-9(3,6-dibromocarbazole) (1.0 g, 2.17 mmol), powdered
anhydrous potassium carbonate (0.45 g, 3.25 mmol), dimethyl
fumarate (DMF, 20 mL) and uracil (0.3653 g, 3.26 mmol). The
reaction vessel was purged with argon and this atmosphere was
maintained throughout the reaction. The reaction mixture was
stirred and heated at reflux in an oil bath at 70.degree. C. for 72
h. Finally, the reaction mixture was filtered, the solvent was
evaporated, and the solid was washed several times with water. The
solid was collected by filtration and recrystallized from toluene
to give crystals (0.54 g, 51%, mp: 190.degree. C.).
.sup.1H NMR (300 MHz, DMSO, .delta.): 11.2 (s, 1H; NH), 7.63 (d,
2H; Ar H), 7.60-7.54 (m, 5H; Ar H), 5.49 (d, 1H; Ar H), 4.39 (t,
2H; CH.sub.2), 3.63 (t, 2H; CH.sub.2), 1.69 (m, 2H; CH.sub.2), 1.58
(m, 2H; CH.sub.2).
.sup.13C NMR (300 MHz, DMSO, .delta.): 164.3, 151.6, 146.1, 139.6,
129.6, 124.1, 123.4, 112.3, 112.0, 101.7, 47.7, 42.9, 26.7,
26.0.
HRMS (ESI, m/z): [M+H].sup.+ calcd for
C.sub.20H.sub.17Br.sub.2N.sub.3O.sub.2, 491.18. found, 491.
E.sub.LEM. Anal. calcd for C.sub.20H.sub.17Br.sub.2N.sub.3O.sub.2:
C, 48.91; H, 3.49; N, 8.56. Found: C, 49.98; H, 3.91; N, 8.56.
EXAMPLE 5
Synthesis of 4-adeninebutyl-9 (3,6-dibromocarbazole) (compound 4,
R=adenine)
As shown in scheme 1, the following reagents were placed in a
reaction flask fitted with a condenser:
4-bromobutyl-9(3,6-dibromocarbazole) (1.0 g, 2.17 mmol), powdered
anhydrous potassium carbonate (0.66 g, 4.77 mmol), anhydrous
N,N-dimethylformamide (20 mL) and adenine (0.44 g, 3.255 mmol). The
reaction vessel was purged with argon and this atmosphere was
maintained throughout the reaction. The reaction mixture was
stirred and heated at reflux in an oil bath at 70.degree. C. for 72
h. Finally, the reaction mixture was filtered, the solvent was
evaporated, and the solid was washed several times with water. The
solid was collected by filtration and recrystallized from toluene
to give crystals (0.59 g, 53%).
.sup.1H NMR (300 Hz, DMSO, ppm): 8.43 (s, 2H), 8.11 (s, 1H), 8.04
(s, 1H), 7.55 (s, 2H), 7.21 (d, 4H), 4.36 (t, 2H), 4.12 (t, 2H),
1.78 (m, 2H), 1.69 (m, 2H).
.sup.13C NMR (300 Hz, DMSO, ppm): 156.7, 153.2, 150.3, 141.3,
139.5, 129.4, 124.1, 123.6, 112.3, 112.0, 43.1, 42.6, 27.8,
26.7.
EXAMPLE 6
Synthesis of 4-octyl-9(3,6-dibromocarbazole) (compound 5)
As shown in scheme 1, the following reagents were placed in a
reaction flask fitted with a condenser: 3,6-dibromo-9H-carbazole
(6.5 g, 0.02 mol), powdered anhydrous potassium carbonate (5.53 g,
0.04 mol), anhydrous acetonitrile (80 mL) and 1-bromooctane (0.2
mol). The reaction vessel was purged with argon and this atmosphere
was maintained throughout the reaction. The reaction mixture was
stirred and heated at reflux in an oil bath at 95.degree. C. for 36
h. Finally, the reaction mixture was filtered, the solvent was
evaporated, and the residue was recrystallized from petroleum ether
to give crystals. (7 g, 80%).
.sup.1H NMR (300 MHz, DMSO, .delta.): 8.07 (d, 2H; Ar H), 7.51 (dd,
2H; Ar H), 7.20 (d, 2H; Ar H), 4.15 (t, 2H; CH.sub.2), 1.77 (m, 2H;
CH.sub.2), 1.20-1.30 (m, 10H; CH.sub.2), 0.85 (t, 3H;
CH.sub.3).
.sup.13C NMR (300 MHz, CDCl.sub.3, .delta.): 139.6, 129.2, 123.6,
123.4, 112.0, 110.7, 43.6, 31.9, 29.5, 29.3, 29.0, 27.4, 22.9,
14.3.
EXAMPLE 7
Synthesis of
1-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl)butyl]--
1,2,3,4-tetra hydropyrimidine-2,4-dione (PTC-U)
##STR00005##
As shown in scheme 2, to a mixture of
4-uracilbutyl-9(3,6-dibromocarbazole) (0.75 g, 1.5 mmol),
4-butyl-N,N-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-4-phenyl)-aniline
(0.82 g, 1.5 mmol), and freshly prepared Pd(0)(PPh.sub.3).sub.4
(0.18 g) was added a deoxygenated mixture of THF (6 mL), DMF (6 mL)
and aqueous 2M K.sub.2CO.sub.3 (8 mL). The mixture was vigorously
stirred at 85-90.degree. C. for 48-72 h. After the solution was
cooled, the whole mixture was poured slowly into a cold mixture of
methanol/deionized water (10/1 in volume). The polymer was
collected by filtration and washed with methanol. The solid was
then washed for 24 h in a Soxhlet apparatus using acetone to remove
oligomers and catalyst residues. The title compound was further
purified by redissolving in DMF and then precipitated from cold
methanol prior to drying at room temperature under high vacuum.
.sup.1H NMR (300 MHz, DMSO-d.sub.6, .delta.): 11.2 (br, NH), 8.54
(br, ArCH), 7.67 (br, ArCH and CH), 7.06 (br, ArCH), 5.48 (br, CH),
4.40 (br, CH.sub.2), 3.63 (br, CH.sub.2), 2.52 (br, CH.sub.2), 1.73
(br, CH.sub.2), 1.63 (br, CH.sub.2), 1.51 (br, CH.sub.2), 1.26 (br,
CH.sub.2), 0.86 (br, CH.sub.2).
EXAMPLE 8
Synthesis of
9-[4-(3-{4-[(4-butylphenyl)(phenyl)amino]phenyl}-9H-carbazol-9-yl)butyl]--
9H-purin-6-amine (PTC-A)
As shown in scheme 2, to a mixture of
4-adeninebutyl-9(3,6-dibromocarbazole) (0.186 g, 0.36 mmol),
4-butyl-N,N-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-4-phenyl)-aniline
(0.2 g, 0.36 mmol), and freshly prepared Pd(0)(PPh.sub.3).sub.4
(0.041 g, 0.036 mmol) was added a deoxygenated mixture of THF (10
mL), DMF (6 mL) and aqueous 2M K.sub.2CO.sub.3 (10 mL). The mixture
was vigorously stirred at 85-90.degree. C. for 48-72 h. After the
solution was cooled, the whole mixture was poured slowly into a
cold mixture of methanol/deionized water (3/1 in volume). The
polymer was collected by filtration and washed with methanol. The
solid was then washed for 24 h in a Soxhlet apparatus using acetone
to remove oligomers and catalyst residues. The title compound was
further purified by redissolving in DMF and then precipitated from
cold methanol prior to drying at room temperature under high
vacuum.
.sup.1H NMR (300 Hz, DMSO, ppm): 8.56 (br, ArCH), 8.17 (br, ArCH),
7.73 (br, ArCH), 7.18 (br, ArCH & NH2), 4.43 (br, CH2), 4.19
(br, CH2), 3.63 (br, CH2), 1.91 (br, CH2), 1.81 (br, CH2), 1.54
(br, CH2), 1.29 (br, CH2), 0.89 (br, CH3).
COMPARATIVE EXAMPLE 1
Synthesis of
N-(4-butylphenyl)-4-(9-octyl-9H-carbazol-3-yl)-N-phenylaniline
(PTC)
As shown in scheme 2, to a mixture of
4-octyl-9(3,6-dibromocarbazole) (0.753 g, 1.5 mmol),
4-butyl-N,N-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-4-phenyl)-aniline
(0.82 g, 1.5 mmol), and freshly prepared Pd(0)(PPh.sub.3).sub.4
(0.041 g, 0.036 mmol) was added a deoxygenated mixture of THF (10
mL), DMF (10 mL) and aqueous 2M K.sub.2CO.sub.3 (10 mL). The
mixture was vigorously stirred at 85-90.degree. C. for 48-72 h.
After the solution was cooled, the whole mixture was poured slowly
into a cold mixture of methanol/deionized water (3/1 in volume).
The polymer was collected by filtration and washed with methanol.
The solid was then washed for 24 h in a Soxhlet apparatus using
acetone to remove oligomers and catalyst residues. The title
compound was further purified by redissolving in DMF and then
precipitated from cold methanol prior to drying at room temperature
under high vacuum.
.sup.1H NMR (300 Hz, CDCl.sub.3, ppm): 8.32 (br, NH), 7.68-7.11
(br, ArCH), 4.31 (br, CH), 2.55 (br, CH.sub.2), 1.88 (br,
CH.sub.2), 1.56 (br, CH.sub.2), 1.30 (br, CH.sub.2), 0.89 (br,
CH.sub.2).
EXAMPLE 9
Gel Permeation Chromatography (GPC) Measurement
To compare the properties of three different materials, PTC, PTC-U
and PTC-A, firstly, the effects caused by their molecular weights
were eliminated by controlling the number-average molecular weights
(Mn) of these three materials between 5000 and 6500, so that the
effects caused by side chains were observed in the following
examples. Through GPC measurements, the molecular weights of three
materials, PTC, PTC-U and PTC-A, relative to that of a standard
(polystyrene) were obtained. The eluent used herein was THF or DMF.
The results are shown in Table 1.
TABLE-US-00001 TABLE 1 Physical Property Material Mn Mw PDI
Repeating Unit Td (.degree. C.) Tg (.degree. C.) PTC 6420 12064
1.88 11 420 150 PTC-U 5089 6868 1.35 8 380 173 PTC-A 5000 8000 1.6
8 405 192
In the following Examples 10 and 11, PTC, PTC-U and PTC-A represent
PTC with 11 repeating units, PTC-U with 8 repeating units and PTC-A
with 8 repeating units, respectively.
EXAMPLE 10
Fourier Transform Infrared Spectroscopy
To verify the formation of hydrogen bonds of three different
materials, PTC, PTC-U and PTC-A, they were dissolved in DMF, cast
onto KBr disks, and dried under vacuum at 70.degree. C.,
respectively. .sup.1H and .sup.13C spectra were recorded using
Varian UNITY INOVA 500 MHz and Varian UNITY 300 MHz spectrometers.
The FTIR spectra for the three materials are shown in FIG. 3. For
PTC, there were not any peak values shown in the range of 3100 and
3700 cm.sup.-1, suggesting that PTC did not contain any N--H bonds.
However, for PTC-U, one peak value at around 3400 cm.sup.-1 showed
free N--H stretch vibration of uracil and one peak value at around
3200 cm.sup.-1 showed bonding N--H stretch vibration of uracil,
suggesting that hydrogen bonds did exist in PTC-U. Likewise, for
PTC-A, one peak value at around 3600 cm.sup.-1 showed free N--H
stretch vibration of adenine and peak values between 3180 and 3450
cm.sup.-1 showed bonding N--H stretch vibration of adenine,
suggesting that hydrogen bonds did exist in PTC-A.
As shown in FIG. 4, for PTC-U, one peak value at around 1750
cm.sup.-1 showed C.dbd.O stretch vibration of uracil. The FTIR
spectra together with the NMR spectra showed the differences among
PTC, PTC-A and PTC-U and demonstrated that the materials were
synthesized as expected.
EXAMPLE 11
Thermal Property
In the application of OLEDs, an element must have a good thermal
property and thermal stability. Therefore, a high thermal decompose
temperature (Td) and a high glass transition temperature (Tg) are
desired properties for a good material.
In this example, Thermal Gravimetric Analyzer (TGA) and
Differential Scanning calorimeter (DSC) were used to obtain the
thermal properties of PTC, PTC-A and PTC-U.
As shown in FIG. 5 and Table 1, it can be seen that all of PTC,
PTC-A and PTC-U had Td of over 350.degree. C., suggesting that they
could sustain high temperatures without decomposition during
operations.
As shown in FIG. 6 and Table 1, it can be seen that the Tg of PTC-U
was 20.degree. C. higher than that of PTC because of the physical
crosslinking by hydrogen bonds, and the Tg of PTC-A was 40.degree.
C. higher than that of PTC because of stronger hydrogen bonding,
suggesting that PTC-U and PTC-A had better thermal stability.
EXAMPLE 12
Solvent-Resistant Ability
The manufacture of elements by polymers is usually conducted by wet
processes. Therefore, solvent-resistant ability is crucial for
polymers, which are usually used in the manufacture of multiple
layers. This example demonstrates that the solvent-resistant
ability of the present invention.
PTC, PTC-U and PTC-A were separately applied on quartz glass
substrates by spin coating to form thin films. Those thin films
were measured by a UV-vis spectrophotometer before and after
toluene were used to rinse the surfaces of those thin films. As
shown in FIG. 7A, the absorbance value of the thin film formed by
PTC significantly decreased after the thin film was treated by
toluene, suggesting that a part of PTC was dissolved in toluene and
left the substrate during rinse. The concentration of PTC
decreased, such that the absorbance value of the thin film thereof
decreased as well. However, as shown in FIGS. 7B and 7C, the
absorbance values for the thin films separately formed by PTC-A and
PTC-U before and after toluene treatment almost remained unchanged,
suggesting that physical crosslinking caused by hydrogen bonding
allowed the polymers hard to be dissolved in general organic
solvents. Therefore, thin films formed by PTC-U and PTC-A would not
be eroded by solvents during wet processes. Such materials made the
wet processes more effective and extend the life time of elements
formed using the same.
EXAMPLE 13
Hole Transport
The thin films formed by PTC, PTC-U and PTC-A respectively were
determined by cyclic voltammetry (CV) to obtain their HOMO and
Lowest Unoccupied Molecular Orbital (LUMO) as shown in Table 2.
TABLE-US-00002 TABLE 2 Parameter of thin film Absorption
Photoluminescence E.sub.ox,onset.sup.b HOMO.sup.c LUMO.sup.d
Solution Film Solution.sup.e - Film.sup.e Thin film Eg.sup.a (eV)
(eV) (eV) (eV) .lamda..sub.max(nm) .lamda..sub.max(nm)
.lamda..sub.m- ax(nm) .lamda..sub.max(nm) PTC 3.08 0.4 -5.2 -2.12
342 347 425 419 PTC-U 3.06 0.36 -5.16 -2.1 338 344 427 423 PTC-A
3.03 0.33 -5.13 -2.1 341 344 424, 506 424 .sup.aEg (energy gap):
obtained from UV-vis spectra (measured in the form of thin film)
.sup.bE.sub.ox,onset: obtained by cyclic voltammetry using
ferrocene as a standard .sup.cHOMO = -E.sub.ox,onset - 4.8 eV
.sup.dLUMO = HOMO + Eg .sup.eExcitation wavelength (.lamda.
excitation = 335 nm)
To compare the ability of hole transport, three hole transport only
structures of ITO/thin film formed by PTC/NPB/aluminium
(abbreviated as Al hereinafter), ITO/thin film formed by
PTC-U/NPB/Al and ITO/thin film formed by PTC-A/NPB/Al were
constructed and determined to obtain the curves of voltage vs.
current. The work function of Al was -4.28 eV and the LUMO of NPB
was -2.6 eV, leading to 1.68 eV of the energy level difference
between them. Since the energy barrier was so big to prevent
electron transport, electrons could not be transported from
negative electrode to positive electrode through the thin film
formed by PTC, PTC-U or PTC-A. It could be ascertained that the
current detected in this example was resulted from hole
transport.
As shown in FIG. 8, under the same voltage, the current density of
the structure with the thin film formed by either PTC-A or PTC-U
was high, suggesting that those thin films had better abilities in
hole injection and hole transport, compared to those of the thin
film formed by PTC. This was because the hydrogen bond formed
between adenine-adenine or uracil-uracil allowed holes to
effectively transport from one main chain to another main chain
nearby. Therefore, the hole transport abilities of the thin films
formed by PTC-U and PTC-A, respectively were improved. By the thin
film formed by PTC-U or PTC-A, holes could be effectively
transported to an emissive layer and allowed a device to emit light
rather than dissipating in the form of heat.
EXAMPLE 14
Hole Injection
Based on the HOMO values, the energy level diagram of FIG. 9 was
obtained. As shown in FIG. 9, it can be seen that the HOMO values
of the thin films formed by PTC-A and PTC-U, respectively were
close to the work function of the ITO glass and the energy level
differences between the thin film formed by PTC-A and the ITO
glass, and between the thin film formed by PTC-U and the ITO glass
were only 0.23 eV and 0.26 eV, respectively, compared to 0.3 eV
between the thin film formed by PTC and the ITO glass, suggesting
that PTC-A and PTC-U were useful in hole injection.
EXAMPLE 15
Element Performance
Three elements having ITO/thin film formed by
PTC/NPB/tris-(8-hydroxyquinoline)aluminum (abbreviated as Alq3
hereinafter)/lithium fluoride (abbreviated as LiF hereinafter)/Al,
ITO/thin film formed by PTC-A/NPB/Alq3/LiF/Al, and ITO/thin film
formed by PTC-U/NPB/Alq3/LiF/Al were constructed and determined,
wherein the thin films were spin coated on the surfaces of the ITO
glasses and the others were formed by evaporation deposition.
As shown in FIG. 10, under the same voltage, the elements with the
thin films formed by PTC-A and PTC-U, respectively had higher
current density, compared to that of the element with the thin film
formed by PTC, suggesting that PTC-A and PTC-U had better abilities
in hole injection and hole transport.
As shown in FIG. 11, the luminescence performances of the elements
with the thin films formed by PTC-A and PTC-U, respectively were
better than that of the element with the thin film formed by PTC.
This was because the hole injection and hole transport abilities of
PTC-A and PTC-U were excellent, leading to more recombination
between holes and electrons, such that more light was emitted.
EXAMPLE 16
Performance of OLED Devices
The present invention may be used in an OLED device, and therefore
three devices were constructed based on the structure of ITO/thin
film (as shown in Table 3)/NPB/Alq3/LiF/Al by the process shown in
FIG. 12. The three OLED devices were evaluated by external quantum
efficiency (EQE, a ratio of photons emitted and holes injected at
the surface of the device), luminescence efficiency (LE) and power
efficiency (PE) to understand the light-emitting performance of
those OLED devices. As shown in FIGS. 13-15, it can be seen that
the EQEs, LEs and PEs of the OLED devices with the thin films
formed by PTC-A and PTC-U, respectively were better than those of
the OLED device with the thin film formed by PTC due to improved
hole injection and hole transport abilities in the OLED devices
with the thin films formed by PTC-A and PTC-U, respectively.
TABLE-US-00003 TABLE 3 Electroluminescence performance of OLED
Device V.sub.on Q.sub.max LE.sub.max .eta.E.sub.max B.sub.max Thin
Film (V) (%) (cd/A) (lm/W) (cd/m.sup.2) PTC 4.4 2 6.8 3 14212 PTC-U
3.5 2.3 8 3.8 43652 PTC-A 3 2.4 8 4.5 47226
EXAMPLE 17
Performance of Elements Having Thin Films Formed by PTC-U/PTC-A
Elements having thin films formed by PTC-U/PTC-A (in ratios of 1:4
and 1:10, respectively) were fabricated and OLED devices having the
aforementioned elements were further constructed. As shown in FIGS.
16A-16D, it can be seen that the element efficiencies of the
elements having thin films formed by PTC-U/PTC-A (in ratios of 1:4
and 1:10, respectively) were further improved, compared to that
having the thin film formed by PTC-A only.
The invention has been described by exemplary preferred
embodiments. However, it is to be understood that the scope of the
invention is not limited to the disclosed embodiments. On the
contrary, it is intended to cover various modifications and similar
arrangements. The scope of the claims, therefore, should be
accorded the broadest interpretation so as to encompass all such
modifications and similar arrangements.
* * * * *